Al-Jazeera writes that the tests "found unnaturally high levels of polonium in Arafat's ribs and pelvis, and in soil stained with his decaying organs." The Guardian notes that the levels of polonium were "at least 18 times higher than the norm in Arafat's ribs, pelvis and in soil that absorbed his leaked bodily fluids."

Other scientists are also studying the samples from Arafat's remains. Al-Jazeera writes that "60 samples of his body tissue were taken and 20 each distributed to the Swiss team, a French team of judges and forensic experts assigned to [a French-led] murder investigation, and a Russian group invited at the request of the Palestinian Authority. The Russians are expected to disclose their results soon. The French are not expected to release their results before the murder investigation concludes."

It was an Al-Jazeera documentary that last year led French authorities to launch a murder probe. Arafat, 75, died in November 2004 at a French hospital. He had been flown to France from the West Bank after falling ill.

The Palestinian leader's death has long been the subject of conspiracy theories and questions.

In 2005, The New York Times wrote that medical records indicated that he "died from a stroke that resulted from a bleeding disorder caused by an unidentified infection." But the Times added that "the records show that despite extensive testing, his doctors could not determine the underlying infection." There's no sign in the Times report that doctors suspected polonium poisoning.

Al Jazeera notes if Arafat was poisoned, then:

"In terms of motive, the chief suspects would be Arafat's Palestinian rivals or the Israeli government, his sworn enemy. Ariel Sharon, the prime minister in 2004, viewed Arafat as a 'terrorist' and called his death 'a turning point in Middle Eastern history.' A year earlier, then-Deputy Prime Minister Ehud Olmert said killing Arafat 'is definitely one of the options.'

"However, Israel has always vehemently denied it had anything to do with Arafat's sickness or death and to date no evidence has emerged that implicates it."

Suha Arafat tells the Guardian she and her 18-year-old daughter, Zahwa, "have to know who did it. We will not stop in our quest to find out."